1. Field of the Invention
This invention relates to a developer cartridge used for replenishing a developer to a developing device which develops a latent image formed on a photosensitive body or the like in an electrophotographic copier and so on.
2. Description of the Related Art
An electrophotographic copier, a laser printer or the like utilizing electrophotography is provided with a developing device for developing an electrostatic latent image on the photosensitive body by using powder toner. The toner is consumed each time an electrostatic latent image on the photosensitive body is developed. And, when the toner runs out, the toner tank of the developing device needs to be replenished with toner.
To simplify this replenishing operation, a detachable cartridge with the toner is mounted in the developing device, and when the developer runs out, the old cartridge is detached and replaced with a new cartridge filled with a developer. As disclosed in Japanese Utility Model Application Laying Open No. 63-14264 "Toner Cartridge for Copier", a box-shaped replenishing cartridge 1 is provide with an opening 2 for supplying the developer into a developer tank of a developing device and a flange portion 4 of the opening 2 is sealed tightly as shown in FIG. 1. The sealing material 3 has one end portion thereof 3a adhered to the face 4a of a side of the flange portion 4 of the container 1 of the developer cartridge. The sealing material 3 is at a middle portion thereof fixed to the face 4b of the opposite side of the flange portion 4 and turned down to cover the opening doubly and cover the end portion 3a of the sealing material fixed to the end face 4a, the other end 3b thereof being left as a free end. By pulling the free end 3b of the sealing material 3 in the arrow direction, the sealing material 3 is peeled from the face 4b of the flange portion 4. By pulling further, the sealing material is gradually separated from the flange portion 4 of the container 1. By this step, a developer filled in the container 1 is replenished to the developing device body through the opening 2 which is open.
The conventional developer replenishing cartridge shown in FIG. 1 requires a force for peeling the sealing material from the cartridge body 1 by pulling the sealing material. To be more specific, when the sealing material is pulled in the direction shown in FIG. 1 (the upward direction intersecting the peeling direction at right angles), the frictional force is large between the fixed end 3a of the sealing material and the overlapping portion 5 of the sealing material at a right-angle bent of the sealing material, and therefore, the force required for peeling off the sealing material 3 is very large. As a result, it is difficult to peel off the sealing material, which has been a problem.